The present invention relates to a false-twist yarn composed of "islands-in-a-sea" type composite filaments, and to a process for the production thereof. More particularly, the present invention relates to a false-twist yarn composed essentially of "islands-in-a-sea" type composite filaments, which filaments can later be made into superfine fibers. The invention also relates to a process for the production of such superfine fibers.
In conventional false-twist yarn, the cross-sectional configuration of each monofilament is crushed due to the forces applied in the false-twisting process, and the cross-sectional configuration established in the initial stage undergoes deformation, adversely affecting the luster and feel of the product.
In the case of an ordinary round cross-section yarn, deformation of the cross-sectional configuration due to false-twisting has not become a particularly serious problem. However, in the case of triangular or penta-lobal filaments which develop luster and harshness of touch, any false-twist process which involves crushing has presented major problems.
On the other hand, since there is no other known means better than false-twisting for imparting bulkiness and stretch-ability to filaments with simplicity and economy, it has long been desired to provide for false-twisting without deforming the cross-sectional configurations of the filaments.
We are aware of Japanese Patent Application Publication No. 35613/1972. However, this publication is directed to mix weaving of a false-twist yarn with a non-false-twist yarn, with an optional possibility of developing crimp.